1. Field of the Invention
The present invention relates to a glass antenna for an automobile, suitable for receiving broadcast signals of radio or television.
2. Discussion of Background
There has been known a glass antenna for an automobile in which an antenna strip having a width of 0.4 mm or less is provided on a rear window glass sheet of automobile in order to assure an excellent viewing field (JP-A-11-243311).
In such conventional antenna strip, however, there is no description about the thickness of the conductor as the antenna strip, and the relation between the thickness of the conductor and the telecommunication characteristics such as sensitivity and so on of the antenna strip, and the relation between the width of the antenna strip and the thickness of the conductor of the antenna strip were unclear. Further, the electrical characteristics of the material used for the antenna strip were also unclear.
Further, in a commercially available automobile, the width of the antenna strip was 0.7 mm or more and the thickness of the antenna strip was about 5 xcexcm. If the thickness of the antenna strip having a width of 0.41 mm or less was determined to be about 5 xcexcm, there might cause deterioration in the telecommunication characteristics. If the thickness was excessively large, it would be difficult to obtain a good sintered product whereby there was a problem of poor productivity.
It is an object of the present invention to provide a glass antenna for an automobile, which can assure an excellent viewing field and which provides good telecommunication characteristics and productivity.
In accordance with the present invention, there is provided a glass antenna for an automobile, comprising an antenna strip obtained by forming a linear silver paste layer on an automobile window glass sheet and firing the silver paste layer, the glass antenna for an automobile being characterized in that:
the electric resistance per unit length of the antenna strip is 0.2 xcexa9/cm or less, and
in the coordinate plane defined by an ordinate which indicates a thickness t(xcexcm) of antenna strip and an abscissa which indicates a width w(mm) of antenna strip, w and t exist in the region surrounded by the following curved line A1, straight line B1, straight line C1 and straight line C4:
t=2.5/w . . . curved line A1,
t=100 . . . straight line B1,
w=0.05 . . . straight line C1 and
w=0.41 . . . straight line C4.
Further, according to the present invention, there is provided a glass antenna for an automobile, comprising an antenna strip obtained by forming a linear silver paste layer on an automobile window glass sheet and firing the silver paste layer, the glass antenna for an automobile being characterized in that:
the electric resistance per unit length of the antenna strip is 0.1 xcexa9/cm or less, and
in the coordinate plane defined by an ordinate which indicates a thickness t(xcexcm) of antenna strip and an abscissa which indicates a width w(mm) of antenna strip, w and t exist in the region surrounded by the following curved line D1, straight line B1, and straight line C4:
t=5.0/w . . . curved line D1,
t=100 . . . straight line B1 and
w=0.41 . . . straight line C4.
Further, according to the present invention, there is provided a glass antenna for an automobile, comprising an antenna strip obtained by forming a linear silver paste layer on an automobile window glass sheet and firing the silver paste layer, the glass antenna for an automobile being characterized in that:
the electric resistance per unit length of the antenna strip is 0.2 xcexa9/cm or less, and
in the coordinate plane defined by an ordinate which indicates a thickness t(xcexcm) of antenna strip and an abscissa which indicates a width w(mm) of antenna strip, w and t exist in the region surrounded by the following curved line A1, straight line E and straight line C4:
t=2.5/w . . . curved line A1,
t=(40/0.3)w+30 . . . straight line E and
w=0.41 . . . straight line C4.
Further, according to the present invention, there is provided a glass antenna for an automobile, comprising an antenna strip obtained by forming a linear silver paste layer on an automobile window glass sheet and firing the silver paste layer, the glass antenna for an automobile being characterized in that:
the electric resistance per unit length of the antenna strip is 0.1 xcexa9/cm or less, and
in the coordinate plane defined by an ordinate which indicates a thickness t(xcexcm) of antenna strip and an abscissa which indicates a width w(mm) of antenna strip, w and t exist in the region surrounded by the following curved line D1, straight line E, and straight line C4:
t=5.0/w . . . curved line D1,
t=(40/0.3)w+30 . . . straight line E and
w=0.41 . . . straight line C4.